Conditional Storage

ABSTRACT

In one aspect of the present disclosure, a method involves obtaining, by a body-mountable device, sensor data, where the body-mountable device includes a data storage. The method further involves making a determination that each condition in a condition set has been satisfied. In addition, the method involves responsive to making the determination that each condition in the condition set has been satisfied, storing the obtained sensor data in the data storage.

BACKGROUND

Unless otherwise indicated herein, the materials described in thissection are not prior art to the claims in this application and are notadmitted to be prior art by inclusion in this section.

A contact lens device can include a sensor for measuring an analyte,such as glucose, in a tear film. The sensor can be an electrochemicalsensor that includes a working electrode and a counter and/or referenceelectrode. An electrochemical reaction involving the analyte cantransfer electrons to or from the working electrode so as to generate acurrent related to the concentration of the analyte. In some instances,a reagent can be located proximate to the working electrode tofacilitate a selective, electrochemical reaction with the analyte.

A contact lens device can also communicate sensor readings to anexternal reader. For example, the contact lens can include an antennathat is configured to receive radio frequency radiation from theexternal reader and produce a backscatter signal based on a sensorreading.

SUMMARY

In one aspect of the present disclosure, a method involves obtaining, bya body-mountable device, sensor data, wherein the body-mountable deviceinclude a data storage; making a determination that each condition in acondition set has been satisfied; and responsive to making thedetermination that each condition in the condition set has beensatisfied, storing the obtained sensor data in the data storage.

In another aspect of the present disclosure, a body-mountable deviceincludes a sensor, a data storage, a processor; and a computer-readablestorage medium having stored thereon program instructions that whenexecuted by the processor cause the body-mountable device to perform afunctions. The functions include obtaining sensor data; making adetermination that each condition in a condition set has been satisfied;and responsive to making the determination that each condition in thecondition set has been satisfied, storing the obtained sensor data inthe data storage.

In yet another aspect of the present disclosure, an eye-mountable deviceincludes a sensor, a data storage, a processor; and a computer-readablestorage medium having stored thereon program instructions that whenexecuted by the processor cause the eye-mountable device to performfunctions. The functions include obtaining sensor data; making adetermination that each condition in a condition set has been satisfied;and responsive to making the determination that each condition in thecondition set has been satisfied, storing the obtained sensor data inthe data storage.

In still another aspect of the present disclosure, disclosed are meansfor obtaining, by a body-mountable device, sensor data, wherein thebody-mountable device include a data storage; for making a determinationthat each condition in a condition set has been satisfied; and for,responsive to making the determination that each condition in thecondition set has been satisfied, storing the obtained sensor data inthe data storage.

These as well as other aspects, advantages, and alternatives, willbecome apparent to those of ordinary skill in the art by reading thefollowing detailed description, with reference where appropriate to theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of an example system that includes abody-mountable device and an external reader.

FIG. 2A is a bottom view of an example eye-mountable device.

FIG. 2B is a side view of the example eye-mountable device shown in FIG.2A.

FIG. 2C is a side cross-section view of the example eye-mountable deviceshown in FIGS. 2A and 2B while mounted to a corneal surface of an eye.

FIG. 2D is a close-in side cross-section view enhanced to show thesubstrate embedded in the transparent material, the light source, andthe emitted light in the example eye-mountable device when mounted asshown in FIG. 2C.

FIG. 3 is a block diagram of an example system that includes multipleexternal readers and a data collection device.

FIG. 4 is a block diagram of an example method.

FIG. 5 is a block diagram of an example computer-readable medium.

DETAILED DESCRIPTION I. Overview

The following detailed description describes various features andfunctions of the disclosed systems and methods with reference to theaccompanying figures. In the figures, similar symbols identify similarcomponents, unless context dictates otherwise. Any reference to “a” or“an” means “at least one” and any reference to “the” means “the leastone” unless otherwise specified or unless context dictates otherwise.The illustrative systems and methods described herein are not meant tobe limiting. It may be readily understood by those skilled in the artthat certain aspects of the disclosed systems and methods can bearranged and combined in a wide variety of different configurations, allof which are contemplated herein.

An electronic device may be utilized to obtain data and to communicatewith other devices or people. The electronic device could be abody-mountable device. In an example embodiment, the body-mountabledevice is an eye-mountable device that can be mounted to an eye. Inother examples, the body-mountable device could be mounted to a tooth,skin, or other body part. The body-mountable device can includecircuitry, a sensor, and an antenna all situated on a substrate embeddedin a biocompatible material. The circuitry can operate the sensor toobtain sensor data. Further, the circuitry can operate the antenna towirelessly communicate information to and/or from an external reader.Generally, the body-mountable device may transmit information to theexternal reader by modulating an impedance of the antenna in a mannerthat is perceivable by the external reader.

In some examples, the biocompatible material is a transparent materialin the form of a generally dome-shaped lens similar to a contact lens.The substrate can be embedded near the periphery of the biocompatiblematerial to avoid interference with vision. The sensor can be arrangedon the substrate to face inward, toward the corneal surface, so as togenerate clinically relevant readings from near the surface of thecornea and/or from tear fluid interposed between the biocompatiblematerial and the corneal surface. Additionally or alternatively, thesensor can be arranged on the substrate to face outward, away from thecorneal surface and toward the layer of tear fluid coating the surfaceof the biocompatible material exposed to the atmosphere.

In some examples, the sensor is entirely embedded within thebiocompatible material. For example, an electrochemical sensor thatincludes a working electrode and a reference electrode can be embeddedin the biocompatible material and situated such that the sensorelectrodes are less than 10 micrometers from the biocompatible surfaceconfigured to mount to the cornea. The sensor can generate dataindicative of a concentration of an analyte that diffuses through thelens material to the sensor electrodes. In other examples, thebiocompatible material includes a channel through which a fluidcontaining the analyte can reach the sensor.

Tear fluid contains a variety of inorganic electrolytes (e.g., Ca²⁺,Mg²⁺, Cl⁻), organic components (e.g., glucose, lactate, proteins,lipids, etc.), and so on that can be used to diagnose health states. Thebody-mountable device can be configured to measure one or more of theseanalytes and can thus provide a convenient non-invasive platform usefulin diagnosing and/or monitoring health states. For example, abody-mountable device can be configured to sense glucose and can be usedby diabetic individuals to measure/monitor their glucose levels. In someembodiments, the sensor can be configured to measure additional or otherconditions other than analyte levels (e.g., light, temperature, andcurrent measurements).

In some instances, the body-mountable device may be configured tointermittently or periodically obtain sensor data. Additionally oralternatively, the body-mountable device may be configured to obtainsensor data in response to receiving a suitable request from theexternal reader. The body-mountable device may also be configured tostore the obtained sensor data in a data storage included in thebody-mountable device, so that the body-mountable device may transmitthe stored sensor data to an external reader at a later time.Additionally, the reader may generate an alert (e.g., that may bepresented on a display screen) that the body-mountable device needs tobe charged.

As noted above, circuitry of a body-mountable device can operate anantenna to wirelessly communicate information to and/or from an externalreader. For example, when the body-mountable device is within a wirelesscommunication range of the external reader, the circuitry can operatethe antenna to receive information from the external reader. In oneexample, such information may include a message querying whether abody-mountable device is within a wireless communication range of theexternal reader (“query message”). In another example, such informationmay include a message requesting the body-mountable device to obtainsensor data and/or to transfer obtained sensor data to the externalreader.

Likewise, provided that the external reader is within a wirelesscommunication range of the body-mountable device, the circuitry canoperate the antenna to transmit information to the external reader. Inone example, such information may include a message that acknowledgesreceipt of a query message and/or identifies the body-mountable device(“acknowledgment message”). As such, in some instances, in response toreceiving the query message from the external reader, the body-mountabledevice may transmit the acknowledgment message to the external reader.This may allow the external reader to detect the presence of thebody-mountable device.

In another example, the information transmitted by the body-mountabledevice to the external reader may include sensor data stored in thebody-mountable device. In some instances, the body-mountable device maytransmit the stored sensor data to the external reader in response toreceiving a suitable request from the external reader. Additionally oralternatively, the body-mountable device may be configured tointermittently or periodically transmit stored sensor data to theexternal reader.

The body-mountable device can be powered in a variety of ways. As oneexample, the body-mountable device may be powered by radio frequencyenergy harvested from an antenna included in the body-mountable device.As another example, the body-mountable device may be powered by lightenergy harvested by a photovoltaic cell included in the body-mountabledevice. As yet another example, the body-mountable device may be poweredby energy stored in a battery included in the body-mountable device. Insome instances, the body-mountable device may employ some combination oftwo or more of these options. For instance, the body-mountable devicemay harvest energy from the antenna and/or the photovoltaic cell, andstore that harvested energy in the battery for later use. Thebody-mountable device may also be powered by other types of powersources.

The external reader can be configured and/or positioned such that theexternal reader and the body-mountable device are within a wirelesscommunication range of each other with some regularity. For example, theexternal reader can be configured to be part of a pair of eyeglasses,jewelry (e.g., earrings, necklace), headband, head cover such as a hator cap, earpiece, and/or other clothing (e.g., a scarf) or device (e.g.,a head-mountable device) that may be worn by a wearer of thebody-mountable device. As another example, an external reader may beconfigured to be part of a case (e.g., a contact lens case) where thebody-mountable device may be stored. In other examples, the externalreader can be positioned in one or more places of a home, workspace,vehicle, or other area where the body-mountable device is likely to bepresent with some regularity. For instance, the external reader may beconfigured to be part of a desk chair at a workplace or part of a sunvisor in a vehicle.

In some instances, multiple external readers may be distributed acrossmultiple positions such as those described above, thereby creating anexternal reader network. With such an arrangement, as a body-mountabledevice moves from place to place, the body-mountable device may fallwithin at least one and perhaps many of the respective wirelesscommunication ranges of the external readers with some regularity.Further, the multiple external readers may be configured to communicatewith each other and/or or with a data collection device so that multipleportions of obtained sensor data retrieved by the various externalreaders can be aggregated together. The external readers or the datacollection device can then utilize the sensor data such as byprocessing, presenting, displaying, storing, communicating, and/orotherwise using the data. Such data may be also encrypted using one ormore known encryption techniques.

As noted above, in some examples, a body-mountable device may obtain andstore sensor data in a data storage of the body-mountable device. Thismay allow the body-mountable device to, at a later time, retrieve thesensor data and wirelessly transmit it to an external reader. Thebody-mountable device may then delete its local copy of the sensor data,thereby increasing available storage space of the data storage. This inturn allows the body-mountable device to store newly obtained sensordata, again for later transmission to an external reader.

In some instances though, such as when the body-mountable device is notwithin a wireless communication range of an external reader, thebody-mountable device may be unable to transmit stored sensor data tothe external reader. This may result in the data storage becoming full,which in turn may prevent the body-mountable device from storing newlyobtained sensor data (i.e., without overwriting the only copy of thepreviously stored sensor data). Also, in some instances, a power sourceof the body-mountable device may unable to provide a threshold amount ofpower, which in turn may prevent the body-mountable device fromobtaining and/or storing additional sensor data.

To help reduce these issues from arising, the body-mountable device maystore sensor data only when certain conditions are met. As such, in oneexample, the body-mountable device may make a determination that eachcondition in a condition set has been satisfied, and in response, thebody-mountable device may store the obtained sensor data in the datastorage.

The condition set may include one or more of a variety of differenttypes of conditions. For example, a condition could be that (i) sensordata obtained by the body-mountable device satisfies one or more datacriteria, (ii) the data storage of the body-mountable device has athreshold amount of available storage space, and/or (iii) a power sourceof the body-mountable is able to provide a threshold amount of energy.

If, in the alternative, the body-mountable device determines that acondition in the condition set has not been satisfied, thebody-mountable device may, at least temporarily, forego the process ofstoring obtained sensor data until after each condition is satisfied.For example, where the data storage of the body-mountable device lacks athreshold amount of available storage space, the body-mountable may waitfor the body-mountable device to transmit stored sensor data to anexternal reader such that the body-mountable device can delete its localcopy of the transmitted sensor data and free up storage space of thedata storage. This may allow the body-mountable device to then (at alater time) determine that the data storage has a threshold amount ofavailable storage space, and in turn store the obtained sensor data.

As another example, where the power source of the body-mountable deviceis unable to provide a sufficient amount of power, the device maysubsequently harvest and/or store additional energy such that the devicemay then (at a later time) determine that the power source is able toprovide sufficient power, and in turn store the obtained sensor data.

II. Example Systems

FIG. 1 is a block diagram of an example system 100 that includes abody-mountable device 110 and an external reader 190.

The exposed regions of the body-mountable device 110 can be made of atransparent material 120 formed to be mounted to a body. In someexamples, the transparent material 120 can be contact-mounted to thebody. In other examples, the transparent material 120 can be embedded inthe body (e.g., surgically embedded, etc.). The transparent material 120can have a mounting surface and a surface opposite the mounting surface.A substrate 130 may be embedded in the transparent material 120 toprovide a mounting surface for a power supply 140, circuitry 150,communication electronics 170, light source 176, and a sensor 178. Thecommunication electronics 170 may include a photo detector 172 and anantenna 174.

The power supply 140 supplies operating voltages to the circuitry 150.The circuitry 150 may provide power to and control the communicationelectronics 170, the light source 176, and the sensor 178. Thecommunication electronics 170 may be operated by circuitry 150 tocommunicate information to and/or from the body-mountable device 110.For instance, the antenna 174 may be operated by circuitry 150 tocommunicate information to and/or from the body-mountable device 110.

For example, when the body-mountable device 110 is within a wirelesscommunication range of the external reader 190, the circuitry 150 canoperate the antenna 174 to receive information from the external reader190. In one example, such information may include a query message. Inanother example, such information may include a message requesting thebody-mountable device 110 to obtain sensor data, store sensor data in adata storage, and/or transmit sensor data to the external reader 190.

In addition, when the external reader 190 is within a wirelesscommunication range of the body-mountable device 110, the circuitry 150can operate the antenna 174 to transmit information to the externalreader 190. In one example, such information may include anacknowledgment message. As such, in some instances, in response toreceiving the query message from the external reader 190, thebody-mountable device 110 may transmit the acknowledgment message to theexternal reader 190. This may allow the external reader 190 to detectthe presence of the body-mountable device 110.

The information transmitted by the body-mountable device 110 to theexternal reader 190 may include sensor data stored in a data storage ofbody-mountable device 110. In some instances, the body-mountable device110 may transmit the stored sensor data to the external reader 190 inresponse to receiving a suitable request from the external reader 190.Additionally or alternatively, the body-mountable device 110 may beconfigured to intermittently or periodically transmit stored sensor datato the external reader 190.

The extent of the wireless communication range of the body-mountabledevice 110 and/or the external reader 190 may depend on various factors,including for example, the particular hardware components used toprovide such wireless communication.

The light source 176 may be operated by circuitry 150 to emit light(e.g., modulated light 186 towards a photodetector 193 of the externalreader 190). Additionally or alternatively, the photodetector 172 andthe light source 176 can be operated by the circuitry 150 to communicateinformation (such as that described above in connection with the antenna174) to and/or from the body-mountable device 110. The sensor 178 mayreceive power and may also be operated by circuitry 150 to provide areading that may be communicated to from the body-mountable device 110.

In some examples where the body-mountable device 110 is an eye-mountabledevice configured to be contact-mounted to an eye, to facilitatecontact-mounting, the transparent material 120 can have a concavesurface configured to adhere (“mount”) to a moistened corneal surface(e.g., by capillary forces with a tear film coating the cornealsurface). Additionally or alternatively, the body-mountable device 110can be adhered by a vacuum force between the corneal surface and thetransparent material 120 due to a concave curvature of the mountingsurface of the body-mountable device 110. In this example, while mountedwith the concave surface against the eye, the outward-facing surface ofthe transparent material 120 can have a convex curvature that is formedto not interfere with eye-lid motion while the body-mountable device 110is mounted to the eye. For example, the transparent material 120 can bea generally dome-shaped polymeric material shaped similarly to a contactlens.

In some examples, the transparent material 120 can include one or morebiocompatible materials. For example, biocompatible materials employedfor use in contact lenses or other ophthalmic applications involvingdirect contact with a body can be used. The transparent material 120 canoptionally be formed in part from such biocompatible materials or caninclude an outer coating with such biocompatible materials. Thetransparent material 120 can optionally include materials configured tomoisturize a surface of the body, such as hydrogels and the like. Insome embodiments where the body-mountable device is an eye-mountabledevice, the transparent material 120 can be shaped to provide apredetermined, vision-correcting optical power, such as can be providedby a contact lens.

The substrate 130 may include one or more surfaces suitable for mountingthe power supply 140, circuitry 150, communication electronics 170,light source 176, and sensor 178. The substrate 130 can be employed bothas a mounting platform for chip-based circuitry (e.g., by flip-chipmounting to connection pads) and/or as a platform for patterningconductive materials (e.g., gold, platinum, palladium, titanium, copper,aluminum, silver, metals, other conductive materials, combinations ofthese, etc.) to create electrodes, interconnects, connection pads,antennae, etc. In some embodiments, through hole pads may be patternedand/or drilled on to the substrate 130 to allow connections betweencomponents on more than one side of the substrate 130. For example, somecomponents like circuitry 150 and communication electronics 170 may bedisposed on one side of the substrate 130 and other components like thelight source 176 and the sensor 178 may be disposed on another side ofthe substrate 130. In some embodiments, the substrate 130 may be amultilayer substrate (e.g., printed circuit board) that allowsconnections between components included in the body-mountable device 110in several layers between multiple sides of the substrate 130. In someembodiments, substantially transparent conductive materials (e.g.,indium tin oxide) can be patterned on the substrate 130 to formcircuitry 150, electrodes, etc. For example, the antenna 174 can beformed by forming a pattern of gold or another conductive material onthe substrate 130 by deposition, photolithography, electroplating, etc.Similarly, interconnects 162, 164, 166, 168 between the circuitry 150and the photodetector 172, antenna 174 light source 176, and sensor 178respectively, can be formed by depositing suitable patterns ofconductive materials on the substrate 130. In some embodiments,interconnects 168 may be similarly formed to connect circuitry 150 withsensor 178.

A combination of microfabrication techniques including, withoutlimitation, the use of photoresists, masks, deposition techniques,and/or plating techniques can be employed to pattern materials on thesubstrate 130. In some examples, the substrate 130 can be a rigidmaterial, such as polyethylene terephthalate (“PET”) or a flexiblematerial, such as polyimide or organic materials configured tostructurally support the circuitry 150 and/or chip-based electronicswithin the transparent material 120. The body-mountable device 110 canalternatively include a group of unconnected substrates rather than asingle substrate. For example, the circuitry 150 can be mounted to onesubstrate, while the light source 172 is mounted to another substrateand the two can be electrically connected via interconnects 162.

In some embodiments where the body-mountable device 110 is aneye-mountable device, the substrate 130 (and other components includedin the body-mountable device 110) can be positioned away from the centerof the body-mountable device 110 and thereby avoid interference withlight transmission to the central, light-sensitive region of the eye(e.g., avoid field of view of the eye). For example, where thebody-mountable device 110 is generally dome-shaped, the substrate 130can be embedded around the periphery (e.g., near the outercircumference) of the dome. In some embodiments, however, the substrate130 can be positioned in or near the central region of thebody-mountable device 110. For example, the body-mountable device 110can be a tooth-mounted device, and the substrate 130 can be embedded inany location inside the transparent material 120. Additionally oralternatively, the substrate 130 (and other components included in thebody-mountable device 110) can be substantially transparent to incomingvisible light to mitigate interference with light transmission to thebody. For example, the body-mountable device 110 can be a skin-mounteddevice, and the substrate 130 can be substantially transparent to allowsunlight to reach the skin.

In some embodiments, the substrate 130 can be shaped as a flattened ringwith a radial width dimension sufficient to provide a mounting platformfor embedded electronics components. The substrate 130 can have athickness sufficiently small to allow the substrate 130 to be embeddedin the transparent material 120 without influencing a shape of thebody-mountable device 110. The substrate 130 can have a thicknesssufficiently large to provide structural stability suitable forsupporting electronics mounted thereon. For example, substrate 130 canbe shaped as a ring with a diameter of about 10 millimeters, a radialwidth of about 1 millimeter (e.g., an outer radius 1 millimeter largerthan an inner radius), and a thickness of about 50 micrometers. However,the diameter, radial width and thickness values are provided forexplanatory purposes only. In some embodiments, the dimensions of thesubstrate 130 can be selected according to the size and/or shape of thebody-mountable device 110. The substrate 130 can optionally be alignedwith a curvature of a surface of the body-mountable device 110.

The power supply 140 may be configured to harvest and/or store energy topower the circuitry 150, communication electronics 170, light source176, and sensor 178. For example, a radio-frequency energy-harvestingantenna 142 can capture energy from incident radio frequency radiation.Additionally or alternatively, photovoltaic cell(s) 144 (e.g., solarcells) can capture energy from incoming ultraviolet, infrared, visible,and/or invisible radiation. In some embodiments, the incident radiofrequency radiation and/or incoming radiation may be ambient radiationin surroundings of the body-mountable device 110. Additionally oralternatively, the incident radio frequency radiation and/or incomingradiation may be from the external reader 190. Furthermore, an inertialpower scavenging system can be included to capture energy from ambientvibrations. The energy harvesting antenna 142 can optionally be adual-purpose antenna that is also used to communicate informationfrom/to the external reader 190. That is, the functions of the antenna174 and the energy harvesting antenna 142 can be accomplished with asame physical antenna.

The power supply 140 may also include a battery 145 for storing energy.The battery 145 may take a variety of forms. For example, the battery145 may take the form of a rechargeable battery such as a nickel-cadmium(NiCd), nickel-metal hydride (NiMH), or lithium ion (Li-ion) battery. Insome instances, the battery 145 may be configured such that it may becharged by an inductive or wireless charging process (e.g., when inclose proximity to a reader configured to charge the battery in thismanner). Additionally or alternatively, the battery may be configured tostore energy harvested via the energy harvesting antenna 142 and/or thephotovoltaic cells 144.

In one example, a rectifier/regulator 146 can be used to conditionharvested and/or stored energy to a stable DC supply voltage 148 that issupplied to circuitry 150. For example, the energy harvesting antenna142 can receive incident radio frequency radiation. Varying electricalsignals on the leads of the energy harvesting antenna 142 are output tothe rectifier/regulator 146. The rectifier/regulator 146 rectifies thevarying electrical signals to a DC voltage and regulates the rectifiedDC voltage to a level suitable for operating circuitry 150. Additionallyor alternatively, output voltage from the photovoltaic cell(s) 144and/or the battery 145 can be regulated to a level suitable foroperating the circuitry 150. The rectifier/regulator 146 can include oneor more energy storage devices to mitigate high frequency variations inthe energy harvesting antenna 142 and/or photovoltaic cell(s) 144. Forexample, one or more energy storage devices (e.g., capacitors,inductors, etc.) can be connected with the outputs of therectifier/regulator 146 to regulate the DC supply voltage 148 and/orconfigured to function as a low-pass filter.

The circuitry 150 is activated when the DC supply voltage 148 isprovided to the circuitry 150. The logic in the circuitry 150 mayoperate the communication electronics 170 to interact with externalreader 190. The logic in circuitry 150 may also operate sensor 178 toobtain sensor data. In addition, the logic in the circuitry 150 mayoperate the light source 176.

In one example, the circuitry 150 may operate the light source 176 suchthat the body-mountable device 110 may communicate with the reader 190.In particular, the circuitry 150 can be configured to receive modulationinstructions and control light source 176 to provide modulated emittedlight 186 towards the photodetector 196 based on the modulationinstructions. Additionally or alternatively, the circuitry 150 may beconfigured to receive the modulation instructions through interactionwith the photodetector 172, antenna 174 and/or sensor 178. In oneexample, the circuitry 150 includes a photodetector interface 152 thatis configured to operate photodetector 172 that may be included in thecommunication electronics 170. The photodetector 172 can be, forexample, an active pixel sensor (APS), charge-coupled device (CCD),photodiode, photoresistor, phototransistor, camera, or any other sensorof light configured to provide a signal through interconnects 162indicative of incident light 182 on the body-mountable device 110. Theincident light 182 may be visible light or invisible light (ultraviolet,infrared, etc.). The incident light 182 detected by the photodetector172 may be indicative of a message, modulation instructions for thelight source 176 included in the body-mountable device 110, or otherdata. For example, the circuitry 150 may modulate light emitted by lightsource 176 based on the message. In other examples, the circuitry 150may control components included in the substrate 130 based on themessage.

In some instances, the circuitry 150 may include an antenna interface154 that is configured to operate antenna 174 included in thecommunication electronics 170 to send and/or receive information viaantenna 174. The antenna interface 154 can optionally include one ormore oscillators, mixers, frequency injectors, etc. to modulate and/ordemodulate information on a carrier frequency to be transmitted and/orreceived by the antenna 174. In some examples, the body-mountable device110 is configured to indicate an output from sensor 178 by modulating animpedance of the antenna 174 in a manner that is perceivable by theexternal reader 190. For example, the antenna interface 154 can causevariations in the amplitude, phase, and/or frequency of radio frequencyradiation (RF radiation) 184 from the antenna 174, and such variationscan be detected by the reader 190. RF radiation 184 may also includeradiation from the reader 190 to the antenna 174. In some examples, thebody-mountable device 110 is configured to receive RF radiation 184 fromthe external reader 190 that is indicative of a message (e.g., a messagerequesting obtained sensor data), the modulation instructions for thelight source 176, or other data. For example, circuitry 150 may modulatelight emitted by light source 176 based on the message. In otherexamples, the circuitry 150 may control components included in thesubstrate 130 based on the message. The antenna interface 154 can beconnected to antenna 174 via interconnects 164.

The circuitry 150 can also include a modulation interface 156 formodulating light emitted by light source 176. The light emitted by lightsource 176 could be visible light or invisible light (ultraviolet,infrared, etc.). The circuitry 150 can include logic elements and/orcontrollers implemented in an integrated circuit to form the modulationinterface 156. For example, the modulation interface 156 can modify anaspect of the emitted light 186 by light source 176 like wavelength(i.e., color), brightness, intensity, or duration of the emitted lightto provide modulated light. The light source 176 may take a variety offorms, including for example a light emitting diode (LED), verticalcavity surface emitting laser (VCSEL), organic light emitting diode(OLED), liquid crystal display (LCD), microelectromechanical system(MEMS), or any other device configured to selectively transmit, reflect,and/or emit light according to information from the modulation interface156 via the interconnects 166 to provide the modulated emitted light186. Also, the light source 176 may be constructed and/or arranged onthe substrate 130 in a particular manner so that the light source 176can emit light in a particular direction (and/or at a particular angle).

In some examples, the modulation interface 156 can include one or moredata lines providing programming information to separately programmedpixels in the light source 176. In some examples, the light source 176may also include one or more optical elements to direct the emittedlight 186 through the surface opposite the mounting surface of thetransparent material 120. In examples where the body-mountable device110 is an eye-mountable device, the light source 176 disposed on thesubstrate 130 can be configured to emit light through the convex surface(e.g., surface opposite the mounting surface) of the transparentmaterial 120 and away from a corneal surface of an eye when the concavesurface (e.g., the mounting surface) of the transparent material 120 ismounted on the corneal surface of the eye.

The circuitry 150 may include a sensor interface 158 for operating thesensor 178. The sensor 178 can be, for example, a bio-sensor configuredto measure an analyte in a tear film. For example, the sensor 178 can bea glucose sensor configured to provide a reading relating to glucoselevel in the tear film. In some examples, the sensor 178 may measureother biological information like blood pressure, temperature, heartrate or psychological state of the user of the body-mountable device110. For example, the sensor 178 can be configured to measure afrequency of eye-blinks to determine the psychological state of theuser. In another example, the sensor 178 can be configured to measurethe concentration of an analyte in saliva (e.g., where thebody-mountable device 110 is a tooth-mounted device). In some examples,the sensor 178 may measure aspects of a surrounding environment of theuser. For example, the sensor 178 may measure the ambient lightintensity or humidity of the surrounding environment. In some examples,the received modulation instructions may be based on the reading of thesensor. For example, the circuitry 150 may be configured to modulate theintensity of the emitted light 186 by the light source 176 according tothe intensity of ambient light indicated by the reading of the sensor178. In other examples, the modulated emitted light 186 may beindicative of the reading of the sensor (e.g., red color may indicatehigh glucose level, blue color may indicate low glucose level, etc.).

In some instances, the body-mountable device 110 may be configured tointermittently or periodically obtain sensor data. In such instances,the external reader 190 may transmit to the body-mountable device 110instructions related to the operation of the sensor 178. For example,the external reader 190 may instruct the body-mountable device 110 touse the sensor 178 to obtain sensor readings according to a particularschedule (e.g., at a particular frequency). Additionally oralternatively, the body-mountable device 110 may be configured to obtainsensor data in response to receiving a suitable request from theexternal reader 190. The body-mountable device 110 may also beconfigured to store the obtained sensor data in a data storage includedin the body-mountable device 110, so that the body-mountable device 110may, at a later time, transmit the stored sensor data to an externalreader 190.

The circuitry 150 is connected to the communication electronics 170 viainterconnects 162 and 164. For example, where the circuitry 150 includeslogic elements implemented in an integrated circuit to form thephotodetector 172 and/or the antenna 174, a patterned conductivematerial (e.g., gold, platinum, palladium, titanium, copper, aluminum,silver, metals, combinations of these, etc.) can connect a terminal onthe chip to communication electronics 170. Similarly, the circuitry 150can be connected to the light source 176 via interconnects 166, and thecircuitry 150 can be connected to the sensor 178 via interconnects 168.

It is noted that the block diagram shown in FIG. 1 is described inconnection with functional modules for convenience in description.However, embodiments of the body-mountable device 110 can be arrangedwith one or more of the functional modules (“subsystems”) implemented ina single chip, integrated circuit, and/or physical component. Forexample, while the rectifier/regulator 146 is illustrated in the powersupply block 140, the rectifier/regulator 146 can be implemented in achip that also includes the logic elements of circuitry 150 and/or otherfeatures of the embedded electronics in the body-mountable device 110.Thus, the DC supply voltage 148 that is provided to the circuitry 150from the power supply 140 can be a supply voltage that is provided tocomponents on a chip by rectifier and/or regulator 146 componentslocated on a same chip. That is, the functional blocks in FIG. 1 shownas the power supply block 140 and circuitry block 150 need not beimplemented as physically separated modules. Additionally oralternatively, the energy harvesting antenna 142 and the antenna 174 canbe implemented with the same physical antenna. For example, a loopantenna can both harvest incident radiation for power generation andcommunicate information via backscatter radiation.

Moreover, one or more of the functional modules described in FIG. 1 canbe implemented by separately packaged chips electrically connected toone another. In another example, one or more of these functional modulesmay be implemented in the form of a processor and a data storage such asa non-transitory computer-readable medium including instructions that,when executed by the processor, cause performance of one or more of thefunctions described in the examples included in the present disclosure.As such, the body-mountable device 110 and/or the circuitry 150 may beconfigured to perform one or more of such functions. The data storagemay also be used for other purposes including, for example, storingobtained sensor data.

The data storage may include a variety of types of memory, including forexample, volatile memory or non-volatile memory. Generally, volatilememory may have an advantage in that it typically takes less energy tostore or retrieve data from volatile memory than from non-volatilememory. However, volatile memory may have a disadvantage in that it maybe unable to maintain stored data without a threshold amount of energybeing provided to it. Accordingly, it may be desired to use a particulartype of memory depending on particular needs.

The external reader 190 can be a smart phone, digital assistant,head-mountable device (e.g., eye glasses with computing capability), orother computing device with wireless connectivity sufficient to providethe RF radiation 184 and/or the incident light 182. The external reader190 can also be implemented as an antenna module and/or light sourcemodule that can be plugged in to a computing device, such as in anexample where the RF radiation 184 operates at carrier frequencies notcommonly employed in computing devices, or in an example where thecomputing device does not include a light source. The external reader190 can also be configured to receive the emitted light 186 from thebody-mountable device 110 via the reader photodetector 196.

The external reader 190 can be configured and/or positioned such thatthe external reader 190 and the body-mountable device 110 are withinwireless communication ranges of each other with some regularity. Forexample, the external reader 190 can be configured to be part of a pairof eyeglasses, jewelry (e.g., earrings, necklace), headband, head coversuch as a hat or cap, earpiece, and/or other clothing (e.g., a scarf) ordevice (e.g., a head-mountable device) that may be worn by a wearer ofthe body-mountable device 110. As another example, an external reader190 may be configured to be part of a case (e.g., a contact lens case)where the body-mountable 110 device may be stored. In other examples,the external reader 190 can be positioned in one or more places of ahome, workspace, vehicle, or other area where the body-mountable device110 is likely to be present with some regularity. For instance, theexternal reader 190 may be configured to be part of a desk chair at aworkplace or part of a sun visor in a vehicle.

As shown in FIG. 1, the external reader 190 may include communicationelectronics 192, a light source 195, a processor 196, and a data storage197, each of which may be connected to each other by a system bus orother connection mechanism 198. The communications electronics 192 mayallow the external reader 190 to communicate information to and/or fromthe body-mountable device 110 or another device (e.g., another externalreader or a data collection device).

In an example where the body-mountable device 110 includes thephotodetector 172, the external reader 190 may include the light source195 configured to provide modulated incident light 182 to thebody-mountable device 110. For example, the modulated incident light 182may indicate the received modulation instructions to the circuitry 150such that the circuitry 150 modulates the emitted light 186 based on thereceived modulation instructions. In another example, the modulatedincident light 182 may include instructions to the body-mountable device110 to obtain a reading of the sensor 178. Thus, in this example, thecircuitry 150 may be configured to modulate the emitted light 186 toprovide modulated light indicative of the reading of the sensor 178.

In some examples, the communications electronics 192 can include aphotodetector 196 to receive the modulated emitted light 186 anddetermine the reading of the sensor 178 based on the modulated emittedlight 186. In some examples, the modulated incident light 182 may beindicative of a status of the external reader 190 or components includedin the external reader 190. In other examples, the modulated emittedlight 186 may be indicative of a status of the body-mountable device 110or a status of components included in the body-mountable device 110. Forexample, the status of photovoltaic cell(s) 144 may be indicated by themodulated emitted light 186. In some examples, the external reader 190can provide light to the photovoltaic cell(s) 144 included in thebody-mountable device 110 that are configured to harvest the light toprovide power to the body-mountable device 110.

In an example where the body-mountable device 110 includes an antenna174, the external reader 190 may include the antenna 194 configured tosend and/or receive information from the body-mountable device 110 viathe RF radiation 184. For example, the antenna 174 may be configured tosend a query message or a message pertaining to the reading of thesensor 178 through RF radiation 184. Thus, the RF radiation 184 may bereceived by the antenna 194 and the reading of the sensor 178 may bedetermined by the external reader 190 based on the RF radiation 184. Insome examples, the antenna 194 may transmit information to thebody-mountable device 110 via the RF radiation 184. In some examples,the external reader 190 may provide the RF radiation 184 to the energyharvesting antenna 142 included in the body-mountable device 110 that isconfigured to harvest the RF radiation 184 to provide power to thebody-mountable device 110.

As noted above, the communication electronics 192 may allow the externalreader 190 to communicate information to and/or from other devices suchas another external reader or a data collection device. In one example,the communication electronics 192 may take the form of a wired orwireless interface and may allow the external reader 190 to communicatewith another device such as the body-mountable device 110, anotherreader 190, or a data collection device according to one or morestandards or protocols; e.g., an RFID standard (e.g., EPC Gen 2), aBluetooth standard, an IEEE 802.11 protocol (“Wi-Fi”), an IEEE 802.15protocol (“Zigbee”), a Local Area Network (LAN) protocol, a WirelessWide Area Network (WWAN) protocol such as but not limited to a 2Gprotocol (e.g., CDMA, TDMA, GSM), a 3G protocol (e.g., CDMA-2000, UMTS),a 4G protocol (e.g., LTE, WiMAX), a wired protocol (e.g., USB, a wiredIEEE 802 protocol, RS-232, DTMF, dial pulse). Many other examples ofstandard(s), protocol(s), and combination(s) of the same can be used aswell. Notably, in some instances, the standard or protocol used mayallow the external reader 190 may communicate with multiple differentbody-mountable devices 110 within simultaneously.

The processor 196 may be configured to control communicationselectronics 192 (including the photodetector 193 and the antenna 194)and the light source 195. The data storage 197 may take the form of anon-transitory computer-readable medium including instructions that,when executed by the processor 196, cause performance of one or more ofthe functions described in the examples included in the presentdisclosure. As such, the external reader 190 may be configured toperform one or more of such functions.

In some embodiments, the system 100 can operate to intermittently supplyenergy to the body-mountable device 110 for the power supply 140. Forexample, incident light 182 and/or RF radiation 184 can be supplied topower the body-mountable device 110 long enough to obtain a reading bythe sensor 178 and wirelessly communicate the reading via emitted light186 and/or RF radiation 184 to the external reader 190. In such anexample, the incident light 182 and/or the RF radiation 184 can beconsidered an interrogation signal from the external reader 190 to thebody-mountable device 110 to request a reading. By periodicallyinterrogating the body-mountable device 110 (e.g., by supplying theincident light 182 and/or RF radiation 184 to temporarily turn thedevice on), the external reader 190 can accumulate a series of readingswithout continuously powering the body-mountable device 110. In anotherexample, the body-mountable device 110 may be configured to use storedenergy in the battery 145 to intermittently obtain sensor data. Theexternal reader 190 may then conditionally retrieve such readings fromthe body-mountable device 110 as described in greater detail below.

The external reader 190 can be configured and/or positioned such thatthe external reader 190 and the body-mountable device 110 are within awireless communication range of each other with some regularity. To thisend, multiple external readers 190 may be distributed across multiplelocations to provide an external reader network. With such anarrangement, as the body-mountable device 110 moves from place to place,the body-mountable device 110 may fall within at least one and perhapsmany of the respective wireless communication ranges of the externalreaders 190 with some regularity. Further, the multiple external readers190 may be configured to communicate with each other and/or with a datacollection device so that multiple portions of obtained sensor data (fora particular body-mountable device) retrieved by the various externalreaders 190 can be aggregated together.

FIG. 3 shown an example system 300 that includes a network of eightexternal readers 190 a-190 h and a data collection device 302. Like theexternal reader 190 described above, the data collection device 302 mayinclude communications electronics, a processor, and a data storage suchas a non-transitory computer-readable medium including instructionsthat, when executed by the processor, cause performance of one or moreof the functions described in the examples included in the presentdisclosure. As shown in FIG. 3, the external readers 190 a-h maycommunicate with the data collection device 302 via respectivecommunication paths 304 a-e. The external readers 190 a-h or the datacollection device 302 can then utilize the sensor data such as byprocessing, presenting, displaying, storing, communicating, and/orotherwise using the data.

As described above, the external readers 190 a-h may attempt to detectthe presence of a body-mountable device 110 in their respective wirelesscommunication ranges by broadcasting a query message. The body-mountabledevice 110 may be configured such that, in response to receiving thequery message, the body-mountable device transmits an acknowledgementmessage back to the external reader 190. The acknowledgement messageallows the external reader to determine the presence of and/or identifythe body-mountable device 110. In some instances, the external reader190 may be configured to intermittently or periodically broadcast aquery message. In other instances, the external reader 190 may transmitsuch a message in response to a request received from a user via a userinterface.

FIG. 2A is a bottom view of an example eye-mountable device 210. FIG. 2Bis a side view of the example eye-mountable device 210 shown in FIG. 2A.It is noted that the relative dimensions in FIGS. 2A and 2B are notnecessarily to scale, but have been rendered for purposes of explanationonly in describing the arrangement of the example eye-mountable device210. The eye-mountable device 210 can be formed of a generallydome-shaped transparent material 220. The transparent material 220 canallow incident light (e.g., field of view of the eye) to be transmittedto the eye while the eye-mountable device 210 is mounted to the eye. Insome examples, the transparent material 220 can be a biocompatiblepolymeric material similar to those employed to form vision correctionand/or cosmetic contact lenses in optometry, such as polyethyleneterephthalate (PET), polymethyl methacrylate (PMMA),polyhydroxyethylmethacrylate (polyHEMA), silicone hydrogels,combinations of these, etc. The transparent material 220 can be formedwith one side having a concave surface 226 (e.g., “mounting surface”,bottom-view surface shown in FIG. 2A, etc.) suitable to fit over acorneal surface of the eye. The opposite side of the dome can have aconvex surface 224 (“surface opposite the mounting surface”) that doesnot interfere with eyelid motion while the eye-mountable device 210 ismounted to the eye. A circular outer side edge 228 can connect theconcave surface 226 and the convex surface 224.

The eye-mountable device 210 can have dimensions similar to a visioncorrection and/or cosmetic contact lenses, such as a diameter ofapproximately 1 centimeter, and a thickness of about 0.1 to about 0.5millimeters. However, the diameter and thickness values are provided forexplanatory purposes only. In some embodiments, the dimensions of theeye-mountable device 210 can be selected according to the size and/orshape of the corneal surface of the wearer's eye.

The transparent material 220 can be formed with a dome or curved shapein a variety of ways. For example, techniques similar to those employedto form vision-correction contact lenses, such as heat molding,injection molding, spin casting, etc. can be employed to form thetransparent material 220. When the eye-mountable device 210 is mountedto an eye, the convex surface 224 faces outward to an ambientenvironment while the concave surface 226 faces inward, toward thecorneal surface. The convex surface 224 can therefore be considered anouter, top surface of the eye-mountable device 210 whereas the concavesurface 226 can be considered an inner, bottom surface. The “bottom”view shown in FIG. 2A is facing the concave surface 226.

A substrate 230 is embedded in the transparent material 220. In someexamples, the substrate 230 can be embedded to be proximate an outerperiphery of the transparent material 220, away from a central region ofthe eye-mountable device 210. Thus, in this example, the substrate 230does not interfere with vision because it is too close to the eye to bein focus and is positioned away from the central region where ambientlight is transmitted to light-sensing portions of the eye. In someexamples, the substrate 230 can be formed of a transparent material tofurther mitigate effects on visual perception.

The substrate 230 can be shaped as a flat, circular ring (e.g., a diskwith a centered hole). The flat surface of the substrate 230 (e.g.,along the radial width) is a platform for mounting electronics such aschips (e.g., via flip-chip mounting) and for patterning conductivematerials (e.g., via microfabrication techniques such asphotolithography, deposition, plating, etc.) to form electrodes,antenna(e), and/or interconnections. In some examples, the substrate 230and the transparent material 220 can be substantially cylindricallysymmetric about a common central axis. The substrate 230 can have, forexample, a diameter of about 10 millimeters, a radial width of about 1millimeter (e.g., an outer radius 1 millimeter greater than an innerradius), and a thickness of about 50 micrometer. However, thesedimensions are provided for example purposes only, and in no way limitthe present disclosure. The substrate 230 can be implemented in avariety of different form factors, similar to the discussion of thesubstrate 130 in connection with FIG. 1 above.

Circuitry 250, a loop antenna 274 and a sensor 278 are disposed on aside of the substrate 230 that is facing the concave surface 226(“bottom side”) of the transparent material 220 as shown in FIG. 2A. Alight source 276 is disposed on an opposite side of the substrate 230that is facing the convex surface 224 of the transparent material 220(“top side”) as shown in FIG. 2B. However, in some embodiments,circuitry 250, the loop antenna 274, the light source 276 and/or thesensor 278 may be disposed on any side of the substrate 230. Forexample, in some embodiments, the circuitry 250 may be disposed in theopposite side (“top side”) of the substrate 230 that is facing theconvex surface 224 of the transparent material 220. In one example, thelight source 276 may be disposed on the side of the substrate 230 thatis facing the concave surface 226 (“bottom side”). In that case, thesubstrate 230 may include a hole through which light emitted by thelight source 276 can reach the convex surface 224 and propagate awayfrom the corneal surface. In some examples, one or more componentsdisposed on the substrate 230 may be disposed on a side of the substrate230 that is facing the circular outer side edge 228 of the transparentmaterial 220.

In some embodiments not illustrated in FIGS. 2A-2B, the substrate 230may include multiple layers for interconnects and other conductivematerial connected to components disposed on the substrate 230. Otherconfigurations of the substrate 230 are contemplated herein. Forexample, one of the multiple layers may be utilized as “a ground plane”for the components to connect to a ground voltage.

The circuitry 250 may include logic elements (e.g., in the form of achip, or a processor and a non-transitory computer-readable medium)configured to operate the loop antenna 274, the light source 276 and thesensor 278. The circuitry 250 is electrically coupled to the loopantenna 274 and the sensor 278, respectively, by interconnects 264 and268. Interconnects 266 electrically connect the circuitry 250 with thelight source 276 through the substrate 230. For example, interconnects266 may be arranged in a through hole connecting the side of thesubstrate 230 that is facing the concave surface 226 (“bottom side”) ofthe transparent material 220 to the opposite side of the substrate 230that is facing the convex surface 224 (“top side”) of the transparentmaterial 220. The interconnects 264, 266, 268, and the loop antenna 274can be formed from conductive materials patterned on the substrate 230by a process for patterning such materials, such as deposition,photolithography, etc. The conductive materials patterned on thesubstrate 230 can be, for example, gold, platinum, palladium, titanium,carbon, aluminum, copper, silver, silver-chloride, conductors formedfrom noble materials, metals, combinations of these, etc. The circuitry250 can be configured to receive modulation instructions and configuredto modulate emitted light 286 from the light source 276 towards aphotodetector of a reader based on the received modulation instructions.

The loop antenna 274 can be a layer of conductive material patternedalong a flat surface of the substrate to form a flat conductive ring. Insome instances, the loop antenna 274 can be formed without making acomplete loop. For instance, the loop antenna 274 can have a cutout toallow room for the circuitry 250 and the sensor 278, as illustrated inFIG. 2A. However, the loop antenna 274 can also be arranged as acontinuous strip of conductive material that wraps entirely around theflat surface of the substrate 230 one or more times. For example, astrip of conductive material with multiple windings can be patterned ona side of the substrate 230 opposite the circuitry 250 and sensor 278.Thus, in this example, interconnects 264 between the ends of such awound antenna (e.g., antenna leads) can then be passed through thesubstrate 230 to the circuitry 250 similarly to interconnects 266 inFIG. 2B.

The light source 276 may take a variety of forms, including for examplea light emitting diode (LED), vertical cavity surface emitting laser(VCSEL), organic light emitting diode (OLED), liquid crystal display(LCD), microelectromechanical system (MEMS), or any other deviceconfigured to selectively transmit, reflect, and/or emit light accordingto received modulation instructions by the circuitry 250 via theinterconnects 266 to provide the modulated emitted light 286. The lightsource 276 may be configured to emit light having any of a variety ofaspects (wavelength, etc.) as described above. Also, the light source276 may be constructed and/or arranged on the substrate 230 in aparticular manner so that the light source 276 can emit light in aparticular direction (and/or at a particular angle). Operation of thelight source 276 is similar to light source 176 discussed in FIG. 1. Thelight source 276 is configured to provide the emitted light 286 throughthe convex surface 224 and away from the corneal surface.

Although illustrated in FIG. 2B that interconnects 266 are connected toone end of the light source 276, some embodiments may include theinterconnects 266 connected to any other part of the light source 276.For example, the interconnects 266 may be arranged underneath the lightsource 276 so that they are not viewable from the “top” side of theeye-mountable device 210 (the side facing the convex surface 224).

The light source 276 may be configured in a rectangular, triangular,circular and/or any shape that is compatible with the flat surface ofthe substrate 230. For example, the light source 276 may have a loopshape similar to the loop antenna 274. The light source 276 may beconfigured to provide the emitted light 286 based on the receivedmodulation instructions by the circuitry 250. For example, the emittedlight 286 may be indicative of a status of the eye-mountable device 210or a status of components included in the eye-mountable device 210. Forexample, the emitted light 286 may be a blinking light that indicatesinsufficient power being provided to the eye-mountable device 210.

The sensor 278 can be disposed on the substrate 230 and configured toprovide a reading to circuitry 250 via interconnects 268. For example,the received modulation instructions may be indicative of the reading ofthe sensor 278. In some examples, the received modulation instructionsmay be a response to radio frequency radiation received by the loopantenna 274 indicative of obtaining the reading from the sensor 278.

FIG. 2C is a side cross-section view of the example eye-mountable deviceshown in FIGS. 2A and 2B while mounted to a corneal surface 20 of an eye10. FIG. 2D is a close-in side cross-section view enhanced to show thesubstrate 230 embedded in the transparent material 220, the light source276, and the emitted light 216, 286 in the example eye-mountable device210 when mounted as shown in FIG. 2C. It is noted that relativedimensions in FIGS. 2C and 2D are not necessarily to scale, but havebeen rendered for purposes of explanation only in describing thearrangement of the example eye-mountable device 210. Some aspects areexaggerated to allow for illustration and facilitate explanation. It isfurther noted that the orientation of the substrate 230 embedded in thetransparent material 220 is not necessarily as shown in FIG. 2D. In someembodiments, the substrate 230 may be oriented at any angle such that anoutward-facing flat mounting surface 234 of the substrate 230 is facingthe convex surface 224 of the transparent material 220 and aninward-facing flat mounting surface 232 of the substrate 230 is facingthe concave surface 226 of the transparent material 220.

The eye 10 includes a corneal surface 20 that is covered by bringing anupper eyelid 30 and a lower eyelid 32 together over eye 10. Ambientlight is received by the eye 10 through the corneal surface 20, wherethe ambient light is optically directed to light sensing elements of theeye 10 (e.g., rods and cones, etc.) to stimulate visual perception. Asillustrated in FIG. 2C, the concave surface 226 is configured to beremovably mounted to the corneal surface 20. Additionally, the convexsurface 224 is compatible with motion of the eyelids 30 and 32.

As illustrated in FIG. 2D, the emitted light 216, 286 from the lightsource 276 is directed away from the corneal surface 20 and through theconvex surface 224 when the concave surface 226 is mounted on thecorneal surface 20. For example, the light source 276 can be disposed onthe outward-facing flat mounting surface 234 of the substrate 230 toallow the emitted light 216, 286 to travel through the convex surface224. In the example, interconnects 266 connect the circuitry 250,disposed on the inward-facing flat mounting surface 232 of the substrate230, to the light source 276 through the substrate 230.

As shown in the cross-sectional views in FIGS. 2C and 2D, the substrate230 can be inclined such that the flat mounting surfaces 232 and 234 areapproximately parallel to an adjacent portion of the concave surface226. However, in some embodiments, the substrate 230 can be oriented atany angle such that the outward-facing mounting surface 234 is facingthe convex surface 224. As described above, the substrate 230 can be aflattened ring with the inward-facing surface 232 (closer to the concavesurface 226 of the transparent material 220) and the outward-facingsurface 234 (closer to the convex surface 224). The substrate 230 canhave electronic components and/or patterned conductive materials mountedto either or both mounting surfaces 232, 234 or through the substrate230 to connect components from one surface to another.

III. Example Operations

FIG. 4 is a block diagram of an example method 400 for operating abody-mountable device in accordance with at least some embodimentsdescribed herein. Method 400 could be used in connection with thedevices 110, 190, and/or 210 for example. Method 400 may include one ormore operations, functions, or actions as illustrated by one or more ofblocks 402-410. Although the blocks are illustrated in a sequentialorder, these blocks may in some instances be performed in parallel,and/or in a different order than those described herein. Also, thevarious blocks may be combined into fewer blocks, divided intoadditional blocks, and/or removed based upon the desired implementation.

In addition, for the method 400 and other processes and methodsdisclosed herein, the flowchart shows functionality and operation of onepossible implementation of present embodiments. In this regard, eachblock may represent a module, a segment, or a portion of a manufacturingor operation process.

At block 402, the method 400 may involve obtaining, by a body-mountabledevice, sensor data, wherein the body-mountable device includes a datastorage. As described above, the body-mountable device may take avariety of forms. For instance, the body-mountable device may take theform of an eye-mountable device. Further, as described above, the datastorage may include volatile and/or non-volatile memory.

At block 404, the method 400 may involve making a determination thateach condition in a condition set has been satisfied. And at block 406,the method may involve responsive to making the determination that eachcondition in the condition set has been satisfied, storing the obtainedsensor data in the data storage. The condition set may include one ormore conditions and each condition may take a variety of forms.

As a first example, a condition may be that the sensor data obtained bythe body-mountable device satisfies one or more data criteria. Forexample, where the body-mountable device is an eye-mountable device, andwhere the obtained sensor data includes sensor data representing aglucose level in a tear film, the first example condition may be thatthe glucose level is above a particular threshold amount. In anotherexample, the first example condition may be that the glucose level isbelow a particular threshold amount. In yet another example, the firstexample condition may be that the glucose level is outside of aparticular range of amounts. By including the first example condition inthe condition set, the eye-mountable device may therefore be configuredfor selectively storing obtained sensor data that is most likely to beof interest to a wearer of the eye-mountable device.

In a second example, a condition may be that the data storage of thebody-mountable device has a threshold amount of available storage space.By including the second example condition in the condition set, thebody-mountable device may therefore avoid a potentially undesirableinstance where the device overwrites certain previously stored sensordata (e.g., data that has not yet been transferred to an externalreader). Notably though, in some instances it may be desired to storethe most recently obtained sensor data even if it means overwritingpreviously stored sensor data, in which case the second examplecondition may not be included in the condition set. Such functionalitymay be provided by configuring the data storage to function as acircular buffer, for example.

In a third example, a condition may be that the body-mountable device isexpected to be able to transmit to an external device at least a portionof its stored sensor data within a threshold amount of time. In someinstances, the condition set may include this third example conditiontogether with one or more other conditions. For example, the conditionset may include both the second and third example conditions such thatthe body-mountable device may selectively store sensor data in a datastorage having a relatively small amount of available storage spaceprovided that the body-mountable device is expected to be able totransmit to an external reader at least a portion of its stored sensordata within a relatively short time period (as this may result in thedata storage then having more available storage space). Likewise, thebody-mountable device may selectively store sensor data in a datastorage when the device is not expected to be able to transmit to anexternal reader at least a portion of its stored sensor data within arelatively short time period provided that the data storage has arelatively large amount of available storage space.

The body-mountable device may determine that it is expected to be ableto transmit to an external device at least a portion of thebody-mountable device's stored sensor data within a threshold amount oftime based on various data maintained by the device, including forexample, historical data indicating the frequency with which thebody-mountable device was able to wireless connect to an external readerand transfer stored sensor data (e.g., the frequency with which thebody-mountable device was within wireless range of the external reader).

In a fourth example, a condition may be that a power source is able toprovide a threshold amount of power to the body-mountable device. In oneexample, where the power source is a battery included on thebody-mountable device, the condition may be that the battery is storinga threshold amount of energy. In another example, where the power sourceis a photovoltaic cell included on the body-mountable device, thecondition may be that the photovoltaic cell is able to provide athreshold amount of power. In another example, where the power source isan external reader, the condition may be that the external reader isaccessible to (i.e., within wireless range of) the body-mountabledevice. By including the fourth example condition in the condition set,the body-mountable device may therefore avoid a potentially undesirableinstance where the device attempts to perform a function when it lackssufficient power to complete the function.

As described above, in some instances the body-mountable device mayharvest energy from an antenna and/or a photovoltaic cell of thebody-mountable device, and store that harvested energy in a battery ofthe body-mountable device for later use. Additionally or alternatively,the battery may be configured such that it may be charged by aninductive or wireless charging process, e.g., when in range of anexternal reader configured to charge the battery in this manner.Notably, this range may be the same as or different that the range thatallows the body-mountable device to transmit sensor data to the externalreader.

In a fifth example, a condition may be that a power source is expectedto be able to provide to the body-mountable device a threshold amount ofpower within a threshold amount of time. In some instances, thecondition set may include this fifth example condition together with oneor more other conditions. For example, the condition set may includeboth the fourth and fifth example conditions such that thebody-mountable device may selectively store sensor data when a powersource is able to provide to the device a relatively small amount ofpower provided that the power source is expected to be able to provideto the device additional power within a relatively short period of time.Likewise, the body-mountable device may selectively store sensor datawhen a power source is not expected to be able to provide to the deviceadditional power within a relatively short period of time provided thatthe power source is already able to provide to the device a relativelylarge amount of power.

In a sixth example, a condition may be that a trigger event occurred. Atrigger event may take a variety of forms, and may include for example,an eye blink of a wearer of the body-mountable device. Other triggerevents are possible as well.

The body-mountable device may determine that the power source isexpected to be able to provide a threshold amount of power to the devicewithin a threshold amount of time based on various data maintained bythe device, including for example, historical data indicating thefrequency with which the power source was able to provide power to thebody-mountable device.

Other example conditions are possible as well. Also, as noted above, acondition set may include one or more of these or other conditions tosuit a described configuration. Further, for a condition that uses aparticular threshold, the threshold may vary to suit a desiredconfiguration.

In some instances, storing obtained sensor data in the data storage mayinvolve storing obtained sensor data in a volatile memory. Additionallyor alternatively, storing obtained sensor data in the data storage mayinvolve storing obtained sensor data in a non-volatile memory. Theconditions in the condition set may be based on properties of either ofthese different types of memory such that the body-mountable device mayselectively store data in a particular one of these types of memorybased on particular factors.

In the event that the body-mountable stores sensor data in volatilememory, the body-mountable device may make another determination thateach condition in another condition set has been satisfied. Andresponsive to making the other determination that each condition in theother condition set has been satisfied, the body-mountable device maytransfer the stored sensor data from the volatile memory to non-volatilememory. The condition set may include one or more of the conditionsdescribed above. However, other example conditions are possible as well.For instance, the condition set may include a condition that thevolatile memory of the body-mountable device has a threshold amount ofused storage space and/or that the non-volatile memory of thebody-mountable device has a threshold amount of available storage space.

In some instances, the body-mountable device may make anotherdetermination that each condition in another condition set has beensatisfied. And responsive to making the other determination that eachcondition in the other condition set has been satisfied, thebody-mountable device may cease the storing of the obtained sensor datain the data storage. The condition set may include one or more of theconditions described above. As such, in one example where the conditionset includes a condition of an eye-blink trigger event occurring, awearer of the body-mountable device may blink to cause thebody-mountable device to cease storing obtained sensor data. Otherexample conditions are possible as well.

In some instances, the body-mountable device may make anotherdetermination that the obtained sensor data has been stored in the datastorage. And responsive to making the other determination that theobtained sensor data has been stored in the data storage, thebody-mountable device may provide an alert. In one example, thebody-mountable device may include a light source and providing the alertmay involve the body-mountable device illuminating the light source(e.g., using a particular blink pattern). However, the body-mountabledevice may provide alerts in other ways as well.

In addition to the body-mountable device selectively storing obtainedsensor data, the device may also selectively transmit to an externalreader, the stored sensor data. As such, at block 408, the method mayinvolve making an additional determination that each condition in anadditional condition set has been satisfied. And at block 410, themethod may involve responsive to making the additional determinationthat each condition in the additional condition set has been satisfied,transmitting to an external device at least a portion of the storedsensor data.

The additional condition set may include one or more conditions and eachcondition may take a variety of forms such as the five exampleconditions discussed above in connection with the function at block 404.

For example, the additional condition set may include the fourth examplecondition that a power source is able to provide a threshold amount ofpower to the body-mountable device. By including the fourth examplecondition in the additional condition set, the body-mountable device maytherefore avoid a potentially undesirable instance where the deviceattempts to transmit sensor data when it lacks sufficient power tocomplete the transmission.

As another example, the additional condition set may include the fourthexample condition and the fifth example condition that a power source isexpected to be able to provide to the body-mountable device a thresholdamount of power within a threshold amount of time. By including theexample fourth and fifth conditions in the additional condition set, thebody-mountable device may selectively transmit to an external readersensor data when a power source is able to provide to the device arelatively small amount of power provided that the power source isexpected to be able to provide to the device additional power within arelatively short period of time. Likewise, the body-mountable device mayselectively transmit sensor data when a power source is not expected tobe able to provide to the device additional power within a relativelyshort period of time provided that the power source is already able toprovide to the device a relatively large amount of power.

The additional condition set may include other conditions as well. In asixth example, a condition may be that the data storage of thebody-mountable device has a threshold amount of used storage space. Byincluding the sixth example condition in the additional condition set,the body-mountable device may therefore avoid a potentially undesirableinstance where the device overwrites certain previously stored sensordata by freeing up available space in the data storage when the deviceis able to do so.

In a seventh example, a condition may be that the body-mountable deviceis within a threshold distance from an external reader. Since it maytake more power for the device to communicate with the external readerwhen the device and the reader are further apart from each other, byincluding the seventh example condition in the additional condition set,the body-mountable device may therefore reduce power consumption bytransferring sensor data to an external reader only when the device iswithin a threshold distance of the external reader.

Other example conditions are possible as well. Also, as noted above, theadditional condition set may include one or more of these or otherconditions to suit a described configuration.

In some examples, the body-mountable device can transmit the obtainedsensor data to the external reader via radio frequency radiation (RFradiation) and/or via light modulation as described above.

FIG. 5 depicts an example computer-readable medium configured accordingto at least some embodiments described herein. In example embodiments,the example system can include one or more processors, one or more formsof data storage or memory, one or more input devices/interfaces, one ormore output devices/interfaces, and machine readable instructions thatwhen executed by the one or more processors cause the system to carryout the various functions tasks, capabilities, etc., described above.

As noted above, in some embodiments, the disclosed techniques (e.g.method 400) can be implemented by computer program instructions encodedon a non-transitory computer readable storage media in amachine-readable format, or on other non-transitory media or articles ofmanufacture. FIG. 5 is a schematic illustrating a conceptual partialview of an example computer program product that includes a computerprogram for executing a computer process on a computing device, arrangedaccording to at least some embodiments disclosed herein.

In one embodiment, the example computer program product 500 is providedusing a signal bearing medium 502. The signal bearing medium 502 mayinclude one or more programming instructions 504 that, when executed byone or more processors may provide functionality or portions of thefunctionality described above with respect to FIGS. 1-4. In someexamples, the signal bearing medium 502 can be a non-transitorycomputer-readable medium 506, such as, but not limited to, a hard diskdrive, a Compact Disc (CD), a Digital Video Disk (DVD), a digital tape,memory, etc. In some implementations, the signal bearing medium 502 canbe a computer recordable medium 508, such as, but not limited to,memory, read/write (R/W) CDs, R/W DVDs, etc. In some implementations,the signal bearing medium 502 can be a communication medium 510 (e.g., afiber optic cable, a waveguide, a wired communications link, a wirelesscommunication link, etc.). Thus, for example, the signal bearing medium502 can be conveyed by a wireless form of the communications medium 510.

The one or more programming instructions 504 can be, for example,computer executable and/or logic implemented instructions. In someexamples, a computing device such as the processor-equipped externalreader 190 of FIG. 1 is configured to provide various operations,functions, or actions in response to the programming instructions 504conveyed to the computing device by one or more of the computer readablemedium 506, the computer recordable medium 508, and/or thecommunications medium 510.

The non-transitory computer readable medium 506 can also be distributedamong multiple data storage elements, which could be remotely locatedfrom each other. The computing device that executes some or all of thestored instructions could be an external reader such as the externalreader 190 illustrated in FIG. 1, or another mobile computing platform,such as a smartphone, tablet device, personal computer, head-mounteddevice, etc. Alternatively, the computing device that executes some orall of the stored instructions could be remotely located computersystem, such as a server. For example, the computer program product 500can implement the functionalities discussed in the description of FIGS.1-4.

It should be understood that arrangements described herein are forpurposes of example only. As such, those skilled in the art willappreciate that other arrangements and other elements (e.g. machines,interfaces, functions, orders, and groupings of functions, etc.) can beused instead, and some elements may be omitted altogether according tothe desired results. Further, many of the elements that are describedare functional entities that may be implemented as discrete ordistributed components or in conjunction with other components, in anysuitable combination and location, or other structural elementsdescribed as independent structures may be combined.

Where example embodiments involve information related to a person or adevice of a person, some embodiments may include privacy controls. Suchprivacy controls may include, at least, anonymization of deviceidentifiers, transparency and user controls, including functionalitythat would enable users to modify or delete information relating to theuser's use of a product.

Further, in situations in where embodiments discussed herein collectpersonal information about users, or may make use of personalinformation, the users may be provided with an opportunity to controlwhether programs or features collect user information (e.g., informationabout a user's medical history, social network, social actions oractivities, profession, a user's preferences, or a user's currentlocation) and an opportunity to control whether or how personalinformation is used. In addition, certain data may be treated in one ormore ways before it is stored or used, so that personally identifiableinformation is removed. For example, a user's identity may be treated sothat no personally identifiable information can be determined for theuser, or a user's geographic location may be generalized where locationinformation is obtained (such as to a city, ZIP code, or state level),so that a particular location of a user cannot be determined. Thus, theuser may have control over how information is collected about the userand how the collected information is used.

While various aspects and embodiments have been disclosed herein, otheraspects and embodiments will be apparent to those skilled in the art.The various aspects and embodiments disclosed herein are for purposes ofillustration and are not intended to be limiting, with the true scopebeing indicated by the following claims, along with the full scope ofequivalents to which such claims are entitled. It is also to beunderstood that the terminology used herein is for the purpose ofdescribing particular embodiments only, and is not intended to belimiting.

What is claimed is:
 1. A method comprising: obtaining, by abody-mountable device, sensor data, wherein the body-mountable devicecomprises a data storage; making a determination that each condition ina condition set has been satisfied; and responsive to making thedetermination that each condition in the condition set has beensatisfied, storing the obtained sensor data in the data storage.
 2. Themethod of claim 1, wherein the body-mountable device comprises aneye-mountable device.
 3. The method of claim 1, wherein the conditionset comprises a condition that the obtained sensor data satisfies one ormore data criteria.
 4. The method of claim 1, wherein the condition setcomprises a condition that the data storage has a threshold amount ofavailable storage space.
 5. The method of claim 1, wherein the conditionset comprises a condition that a power source is able to provide athreshold amount of power to the body-mountable device.
 6. The method ofclaim 5, wherein the power source comprises a battery included in thebody-mountable device, and wherein the condition that the power sourceis able to provide the threshold amount of power to the body-mountabledevice comprises a condition that the battery is storing a thresholdamount of energy.
 7. The method of claim 5, wherein the power sourcecomprises a photovoltaic cell included in the body-mountable device. 8.The method of claim 1, wherein the power source comprises an externaldevice, and wherein the condition that the power source is able toprovide the threshold amount of power to the body-mountable devicecomprises a condition that the external device is accessible to thebody-mountable device.
 9. The method of claim 9, wherein the externaldevice provides power to the body-mountable device wirelessly.
 10. Themethod of claim 1, wherein the condition set comprises a condition thata power source is expected to be able to provide a threshold amount ofpower to the body-mountable device within a threshold period of time.11. The method of claim 1, further comprising: making an additionaldetermination that each condition in an additional condition set hasbeen satisfied; and responsive to making the additional determinationthat each condition in the additional condition set has been satisfied,transmitting to an external device at least a portion of the storedsensor data.
 12. The method of claim 1, wherein storing the obtainedsensor data in the data storage comprises storing the obtained sensordata in volatile memory.
 13. The method of claim 12, further comprising:making another determination that each condition in another conditionset has been satisfied; and responsive to making the other determinationthat each condition in the other condition set has been satisfied,transferring the stored sensor data from the volatile memory tonon-volatile memory.
 14. The method of claim 1, wherein storing theobtained sensor data in the data storage comprises storing the obtainedsensor data in non-volatile memory.
 15. The method of claim 1, whereinthe condition set comprises a condition that a trigger event occurred.16. The method of claim 15, wherein the trigger event comprises an eyeblink of a wearer of the body-mountable device.
 17. The method of claim1, further comprising: making another determination that each conditionin another condition set has been satisfied; and responsive to makingthe other determination that each condition in the other condition sethas been satisfied, ceasing the storing of the obtained sensor data inthe data storage.
 18. The method of claim 17, wherein the othercondition set comprises a condition that a trigger event occurred. 19.The method of claim 18, wherein the trigger event comprises an eye blinkof a wearer of the body-mountable device.
 20. The method of claim 1,further comprising: making another determination that the obtainedsensor data has been stored in the data storage; and responsive tomaking the other determination that the obtained sensor data has beenstored in the data storage, providing an alert.
 21. The method of claim1, wherein the body-mountable device comprises a light source, whereinproviding the alert comprises illuminating the light source.
 22. Abody-mountable device comprising: a sensor; a data storage; a processor;and a computer-readable storage medium having stored thereon programinstructions that when executed by the processor cause thebody-mountable device to perform functions comprising: obtaining sensordata; making a determination that each condition in a condition set hasbeen satisfied; and responsive to making the determination that eachcondition in the condition set has been satisfied, storing the obtainedsensor data in the data storage.
 23. The body-mountable device of claim22, wherein the body-mountable device comprises an eye-mountable device.24. The body-mountable device of claim 22, wherein the condition setcomprises a condition that the obtained sensor data satisfies one ormore data criteria.
 25. The body-mountable device of claim 22, whereinthe condition set comprises a condition that the data storage has athreshold amount of available storage space.
 26. The body-mountabledevice of claim 22, wherein the condition set comprises a condition thata power source is able to provide a threshold amount of power to thebody-mountable device.
 27. The body-mountable device of claim 22,wherein the condition set comprises a condition that a power source isexpected to be able to provide a threshold amount of power to thebody-mountable device within a threshold period of time.
 28. Aneye-mountable device comprising: a sensor; a data storage; a processor;and a computer-readable storage medium having stored thereon programinstructions that when executed by the processor cause the eye-mountabledevice to perform functions comprising: obtaining sensor data; making adetermination that each condition in a condition set has been satisfied;and responsive to making the determination that each condition in thecondition set has been satisfied, storing the obtained sensor data inthe data storage.